To construct PGSs we applied the LDpred39 method to the sex-specific GWAS summary statistics from the UK Biobank for total T, SHBG, FAI and free T, using 1000 Genomes Europeans as LD reference and the default LD radius to account for LD. For co-localization analyses to assess whether the genetic loci showed evidence for shared genetic effects between males and females, and to estimate the maximum posterior probability (MAP) for the loci being shared, we used gwas-pw37. Our study design comprised of several steps to ensure robustness of the findings, and the conclusions of the study are based on multiple converging statistical analyses and vast datasets.
Nuclear receptors are also known to play an important role in the aging process. In case of TORC1 induces longevity of life, SKN-1/Nrf are required and presence of DAF-16/FOXO is not obligatory (Figure 4). Genetic interference to inhibit the translation process has been linked with the longevity of life in C. Longevity of lifespan regulated by IIS pathway via DAF-16/FOXO, TOR pathway vis SKN1/Nrf and FOXO regulation, and by JNK under oxidative stress by phosphorylation and inactivation of IRS1 and activation of AKT. The main consequences of this cascade include the promotion of glucose transport, protein synthesis, cell proliferation, cell differentiation, and inhibition of apoptosis that enhance the longevity. The circadian desynchrony may lead to the neurodegenerative disorders and metabolic pathologies that ultimately impact the lifespan . DNA damage triggers aging process by blocking transcription, activating the signal transduction processes, regulating the DNA metabolism, altering the epigenome and finally by inducing apoptosis 310,311,312.
The "Lifepath" research consortium investigated the effects of socioeconomic inequalities on the biology of successful aging. Therefore, prenatal exposure to maternal flu, even uncomplicated, can have consequences on future extrauterine life, likely through epigenetics . Both articles refer, indeed, to a low prediction of descendant longevity based on the ages reached by their ancestors/parents.
Six European-ancestry GWAS of human aging traits, i.e., health span, father and mother lifespan, exceptional longevity, frailty index, and self-rated health, have been combined in a principal component framework to maximize their shared genetic architecture . Althoughresults on the effects of estradiol on muscle structure and contractile function in humansare conflicting (188) and depend on speciesexamined, study type, age, muscle size, and fiber type etcetera (75), two recent well-controlled studies show beneficial effects ofhormone replacement therapy on skeletal muscle composition and function in postmenopausalwomen (88,189). More studies areneeded to investigate whether the relative low testosterone levels in women may contributeto conditions later in life, such as mobility impairment, that are linked to disability,reduced quality of life and mortality and whether testosterone replacement therapy canreduce the negative health consequences of age-related frailty. Hormonal changes and theirpotential effects on inflammation may, in part, affect conditions, such asatherosclerosis, cardiovascular diseases, metabolic syndrome, and type 2 diabetes.Although the role of sex hormones on aging and age-related diseases is still unclear,there are clear age associations, which are likely reducing healthy aging and negativelyimpacting longevity. Yet we stress the unique genetic architecture of serum T levels, potentially reflecting sexually antagonistic effects of T on fitness, and emphasize the causal role of the hormone also for women’s health.
Several environmental and physiological factors contribute to the aging process. The challenge, he says, is balancing the benefits and the risks. Pike says there is promising research focusing on what can be done to turn on the brain's own testosterone-making system. "We know that prostate tumours respond to testosterone with incredible growth." He says further long-term research is needed to fully understand the way testosterone affects the body. Studies have shown that they are involved in age-related changes, such as the development of dementia.
We greatly thank all UK Biobank, the Young Finns study, and FinnGen participants, as well as the principal investigators, laboratory personnel and data management teams behind these efforts. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. Besides the gained medical insight, underscoring some critical factors that should be considered when assessing these connections, our study therefore provides a novel reference point for future genetic and epidemiological studies on T. Finally, the data used in our study does not allow for assessing the effects of acute changes in hormone secretion, including those happening during different phases of the menstrual cycle in females or upon certain environmental stimuli, and personal differences in responses to such fluctuations.
Our setting thus may not allow for assessing the effects of fetal T exposure, which may be critical, e.g., for neurological traits82, or serum T may not be the optimal androgen to assess such risk associations. Given the combination of analysis strategies—for the MR estimates, 1 SD change in circulating T levels as the basic unit—we were well positioned to detect any substantial effects normal variation in adult T levels, excluding clinical conditions, would have on disease and health. We however stress that our genetic data clearly suggests that many different biological processes are involved in determining normal variation in T levels, serum T levels likely serving only as a proxy for T action in tissues. Although we cannot conclude that the action of T drives these associations, the result agrees with sex-specificity in the genetic disease mechanisms for stroke66.